I work for a botanical center, and we have a very special set-up. We have a mini-Mississippi river, that is essentially a wading pool for kids. I have an underground reservoir that hold about 3,800 gallons. We have a pump that moves the water from the reservoir to top of the river, where it flows through grates in the delta that drain back into the reservoir. Our river flows between perennial beds, and kids often add sticks, mulch, sand, other organic things found in a garden, to our water system.

We have a Chemtrol ORP and pH reader, and use acid and liquid chlorine auto-injectors to sanitize the water. I am having a difficult time balancing a good ORP level with a FC level that is within state standards of 2-4. The mechanicals add CL to clean the water, but then FC levels are too high. What other steps can I take to help the ORP be higher without too high FC levels?